Many people envision a large, branching taproot growing deep into the soil. Actually, taproots are very uncommon in mature trees. If taproots do develop, they usually will be forced into horizontal growth when they encounter hard subsoils beneath the surface. The entire root systems of most trees can be found within 3 feet of soil. The spread of the root system however, can be very extensive, often extending 2 to 3 times the spread of the crown.